Immersion is immensely different than Diablo II: Lord of Destruction; it features many changes not listed below.

Difficulty

• Skill group bonuses from equipment are very rare. (+x to All Skills, etc.)
• Characters begin play with a potion that can immediately increase your attributes and unlock skill tiers earlier.
• Hardcore mode is immediately available. /Players X is disabled.

Aesthetics

• New and recolored images and animations are included for various items, missiles, enemies, and maps.
• The majority of the graphical user interface is redesigned, to darken and enhance the visual quality of the game.
• Text throughout the entire game is less confusing and descriptions are written more sensibly. Font size has decreased and text colors are expanded.

Skills

• Skills have prerequisite attributes by class. There are no longer prerequisite skills, level requirements, or maximum skill levels.
• Characters can select new, old, and hybrid skills across the skill trees of all characters.
• Many skills have entirely new synergy bonuses and investment (hard point) synergies.

Enemies

• You can test your mettle against new enemies, new superuniques, and improved traps. New boss fights also await you.
• Enemies are stronger, tougher, quicker, plentiful, and varied. Many have more aggressive AIs. Some have new skills at their disposal.
• All unique enemies have new randomly-generated names and the majority of enemies are identified by new descriptions.

Areas

• There are no longer any dirt paths running throughout the wilderness of Act 1. You must forge your own path.
• There is a wildly different secret level to discover and there are no restrictions whatsoever on returning to it.
• Shrines no longer reveal their true purposes until used. Their effects stack with each other and are no longer nullified by curses.
• New maps of Lut Gholein and Kurast (by Dyze) increase your efficiency in town in Act 2 and Act 3.
• The caves in Act 1 have recolored tiles (by SheX).

Character

• Character movement speed is increased and defense is no longer negated while running.
• Character life no longer replenishes naturally and potions are both less abundant and less effective.
• Character default light radius is decreased to darken gameplay.

Hirelings

• Hireling vendors can dismiss your hireling before a dangerous battle, refunding half of their current resurrection gold cost.
• Hireling resurrection costs are decreased to keep them alive and hireling movement is increased to better keep pace with characters.
• Hireling-Only items (uniques, set items, runewords, etc.) give your merc new advantages in combat, but devour your life if you equip them.

Economy

• Items are sold to vendors at a fraction of their prices. Vendors no longer sell magic items and may not sell yours back to you.
• Gold is far more scarce than it used to be. Gold is more likely to drop from objects such as chests and unique/champion enemies.
• Gambling odds (Rare, Set, and Unique) are significantly improved on all difficulties and gambling prices are much lower.

Items

• Level requirements are non-existant. Supplying lower-level characters is to be considered a reward earned alongside your level.
• Characters have an expanded inventory, stash, and horadric cube. If that isn't enough space, PlugY (by Yohann) is included for near-unlimited storage.
• Alchemical potions are sold by vendors, while weaker potions are only dropped by enemies. These varieties work well together. Belts hold potions by difficulty.
• Global treasure tables have been optimized for challenging, fast gameplay. Many new affixes and magical properties enhance items found throughout the game.

• Magic Items: Magic items no longer require identification, which is costly. Identify scrolls are now quite hard to come by.
• Unique Items: You can find all of the original unique items and many new unique items. Characters start with a special new unique: the Horadric Soulsphere.
• Set Items: You can find all of the original item sets and some new item sets. Each class has a new exceptional set and the original class sets are now composed of elite items.
• Runewords: You can create all of the original and ladder runewords along with many new runewords, jewelwords, gemwords, and soulwords.
• Alchemical Reagents: You can find alchemical reagents throughout the game, which enhance certain items in various ways.
• Equipment Crafting: Characters now possess crafting skills to complement their equipment, if desired.
• Equipment Tempering: You can purchase tools from a vendor and add the statistics you desire to your choice of equipment.
• Superior/Inferior Items: High quality items can spawn with improved properties and low quality items have new uses also.
• Inventory Charms: All charms are retitled with new graphics. Battle Standards (new 2x3 charms) are introduced.

Misc

• Immersion runs on any version of Lord of Destruction.
• Immersion auto-saves your character after you activate a new waypoint.
• Saved games and shared stash files are now automatically backed up during game launch. (..\Diablo II\Immersion\Save\*.backup)
• Screenshots taken in Immersion are dated, timestamped, and moved to their own subfolder on game exit. (..\Diablo II\Immersion\Screenshots\*.jpg)
• An optional No-CD Loader (by Corni) is included, to play without spinning your CD-ROM to death. See the installation page for additional information.

Immersion v1.05 beta 1.05c (Patch Installer)
• Items: Increased staff missile damage from 1/4 weapon damage to 1/2 weapon damage
• Items: Auto-retrieval of gold is improved and gold can no longer be auto-retrieved by a player with corpses
• Properties: Poison damage affixes now have a one second base length and zero poison damage affixes should no longer spawn on items
• Quests: The Act 2 orifice interface no longer crashes the game
• Vendors/NPCs: The second imbue/socket/personalize interface button no longer displays the text "Refresh" on mouse hover

Immersion v1.05 beta 1.02 (Installer)
• Areas: The automap (minimap) no longer crashes the game in Act I (wilderness or secret level)
• Client/Misc: Mod version is now displayed on the personal journal rather than the main menu
• Client/Misc: PlugY.exe is no longer included in the installation, as it is unnecessary
• Enemies: A new enemy infests the Dry Hills in Act II
• Enemies: Corrupt Rogues movement speed is decreased
• Enemies: Fallen Realm Portals have a longer delay between spawning (Normal and Nightmare difficulty)
• Items: Gems have a different drop sound
• Items: The attunement recipe functions correctly for Barbarians
• Items: Glyphs should now drop correctly in the intended areas
• Items: Corrected the description on the platinum soul shard
• Vendors/NPCs: Akara now has new lore dialogues explaining attunement and unsocketing